data class Coordinate3(var x: Int, var y: Int) {
    val isInBounds = x > 0 && y > 0

    operator fun plus(other: Coordinate3) = Coordinate3(x + other.x, y + other.y)
}

fun main() {

    val c1 = Coordinate3(10, 20)
    val c2 = Coordinate3(10, 20)

    println(c1 + c2)
}